From unipolarity to bipolarity: Systemic transformation and the emergence of post-unipolar international politics

With the decline of U.S. unipolarity and the rise of Sino-American bipolarity, this article explores a conceptualization of systemic transformation in international politics and its implications for outcomes in state behaviors during the transition. Neorealist theory, which emphasizes the impact of relative power redistribution among great powers, provides a valuable framework for understanding these changes. While often criticized for being overly static and limited in scope, the theory contains a subtle theory of change that can be leveraged to offer new insights into the ongoing transformation of the international system. The article develops four propositions from neorealist theory: disruptions in system-wide patterns of interstate rivalry and conflict, general realignment, increased occurrences of state "births and deaths," and waves of political regime changes, including de-democratization in the present case of emerging Sino-American bipolarity. These propositions are applied to the current transition, with preliminary evidence suggesting that neorealism can serve as a powerful analytical lens to further our understanding of the transformation toward a new bipolar world.